Windows XP Unofficial SP4 is a cumulative update rollup for Windows XP (x86). It can be applied to a live Windows XP system which has SP1, at minimum, installed or it can be slipstreamed (integrated) in any Windows XP installation media.

It includes updates for most Windows XP components, including MCE and Tablet PC. Request-only hotfixes have been included. Currently, Microsoft .NET Frameworks 4.0, 3.5, 1.1 and 1.0 (Tablet PC only) are included in the Windows XP SP4 package. You can also scan for POSReady updates, because the POSReady trick has been included. In addition, all post-eol updates for .NET Framework 1.1, 3.5 and 4.0 until May 2014 have been included.

cool update but it still is unstable on tablet pc edition windows xp and even more unstable on the windows xp media center edition and still doesnt stop the malware and virus problems associated with this old but great o.s